This is one of the few times I will ever disagree with Penfold. Take Feral Elder Thing, which reads something along the lines of "At the beginning of your turn, each player discards 2 cards. Then each player draws 1 card." I know this is a slightly different scenario, but the resolving works the same way IMO. If one of the players cannot discard 2 cards (i.e., they have 1 or 0 cards in hand) then drawing cannot occur.

In short, if you have 3 cards in your hand, and someone plays Apeirophobia on your Twilight Cannibal, he can't go insane, and you can't discard 4 cards, and those are the 2 options for which the card allows. Therefore, your opponent foolishly wasted the resources to play that card.

 Yey, and im not even part of this rant. But from what i managed to learn re reading FAQ over and over:

Action: Choose a non-AO character.// preaty simple, may have T or willpower nothing preventing it

// now next

That character's controller chooses to either

 - have that character go insane // it is impossible to >>choose<< him to go insane

or

 - discards X cards from his hand. // it is possible to discard some cards, though not all

X is the skill of the chosen character.

FAQ to the rescue:

(1.5) Choosing Targets

The word target is used to indicate that an effect is directing a player to choose 1 or more cards for an effect to resolve on. Not every effect that resolves on a card is targeted. An effect that resolves on 1 or more cards without specifically using the word “choose” is not a targeted effect. A player cannot trigger a card effect that requires him to choose a character, support card, or story card if there is no card of that type that he is able to choose. For example, a player could not play Opening the Limbo Gate (Core Set F116) unless every player’s discard pile contained at least one character card. In addition, a player cannot trigger a card effect that requires him to choose a certain number of targets if there are not enough valid targets available. Also note that if a card is targeted, but becomes an illegal target (e.g., via a Disrupt: action), the targeting effect is then ignored. For example, if Darrin plays the triggered ability on Slavering Gug (Core Set F124) on Tommy’s Jack “Brass” Brady (Core Set F61), Tommy may choose to use Jack “Brass” Brady’s Disrupt: action, which would return him to Tommy’s hand. Assuming both players subsequently pass, the Slavering Gug’s ability now resolves. However, since Jack “Brass” Brady is no longer in play and is thus an illegal target, the Slavering Gug’ s effect is ignored.

(1.8) Eligible Targets

In order to target a card with an effect, that card must meet the targeting requirements. Any part of the effect for which that character is ineligible is simply ignored. For example, with Brain Transplant (Summons of the Deep F111) you may target one insane character and one ready character who are both controlled by the same player, as per the targeting requirement. If the ready character has Willpower or a T icon, it is ineligible for the second part of the card’s effect (“The ready character goes insane, if able”), so that part of the effect is ignored.

Ouch… especially 1.8 is confusing as hell… if able in this example is misleading, as interpreting this point requires getting if able semantics, what it refers to is actualy "if able" not normal targeting requirement… IMO 1.8 needs rework.

1.5 actually applies here as it states clearly no choose - no targeted effect, no check; if you choose you have to choose what is a good target.

so insane no, but can you discard cards

again no… hmm when i started writing this post i thought you can because there is no choose in sight, but it was in the first part of sentance so it affects both parts but is really easy to fail to see second part is also a "choose" type effect… i was thinking im describing Penfolds point of "no choose so do as much as you can"

Still I need to think of a way to reword this as current wording is horrible to understand…wow, this time its quite hard as it really breaks down to

Choose one you can do completely: choose that character to go insane, choose and discard X cards from hand. … this is a tough one

 [edit]

ok now im 90% sure this card breaks some of those conventions by sloppy wording… this first chooses can refer to the choice of an alternative way, or the choice of getting this character go insane or to the choice of X cards to discard, but with the last one grammar form doesn't match

… real Hastur indeed, wants to drive actual players mad…

 Cards are drawn and discarded singularly. Because you are not told to choose a subset of cards but to discard X cards you discard each card until you reach the number X. Page21 from the faq -

"Julia Brown, Oddly Amphibious (Summons of the Deep F107), reads, “Forced Response: After Julia Brown commits to a story, discard 2 cards at random from your hand, then draw 2 cards.” If I have only 1 card in hand when I commit her, must I discard this card or not? Can I draw 2 cards?

Yes you must discard your 1 card. You must seek to fulfill as much of a card’s effect as possible. Since cards are drawn or discarded singularly you must discard cards in your hand until you have reached the maximum of 2 for this effect. However, since the next part of Julia’s effect is a “Then” statement, because you were unable to successfully discard 2 cards you may not draw any cards."

What makes this different from some other effects as I said is the lack of the word choose, which forces you to be able to target a specific number of cards. If you cannot choose them the effect fails entirely. However without that designator you must attempt to discard cards from your hand individually until you have either reached the number the effect states or until you can no longer discard cards.

It should be noted here that the "then" clarification directly applies to the Feral Elder Thing argument that was being made earlier. Unable for both individuals to choose and discard 2 cards, no one gets to draw any cards because the first effect was not successful. PErsonally I wish the wording did allow for each person who was able to successfully discard 2 cards to draw a card, but that isn't how it is done in AGoT which has the same designer and same wording. The FAQ does seem to have that one spot where we can hold out a glimmer of hope, but given it is not in a section about that at all and does not precisely say that it works that way I'm not holding my breath (but I am keeping my fingers crossed).

See? This is why I hardly ever disagree with you. You're a better rules lawyer than me

 I prefer the term rules philosopher. :P

Thank you, Penfold.